Wow, you came up with cool clamps for the microphone arm under the marimba. In college we had stands right in front of the musician's head. Sometimes they were hit with chopsticks and there was a rumble in the control room!!! I noticed that you have one synth going through a stereo dibox, and the second synth through two mono diboxes, is that more convenient? What microphone cable do you use for indoor sound? Do you have any favorite brands? Show us your soldering shop. Very interesting!